Behavioural Study on Geomaterial Undergoing Chemo-Mechanical Degradation

Abstract

The behaviour of any granular media primarily depends on the packing of grains. Any process that alters the packing of the granular assembly has a direct influence on its strength properties. Dissolution is one such processes, which induces a change in the grain size and thereby the index properties of the granular material change. In the present study, the response of carbonate sand to chemo-mechanical loading is experimentally analysed using a modified oedometer test setup capable of measuring both vertical and lateral stresses. Two sets of coupled chemo-mechanical experiments are performed to explore the variation of the rate of dissolution. In the first set, the corrosive fluid used for degradation is kept stagnant thereby varying the reaction rate. In the second set, the fluid is in flowing condition, maintaining the degradation rate almost constant. Our aim is to observe the variation in the lateral earth pressure coefficient with the two types of dissolution processes. Here the degree of dissolution is quantified by a chemical state variable defined in terms of mass loss with reference to the initial mass. The results show a rapid initial decay in the lateral earth pressure coefficient followed by an increasing or stable trend, depending on the type of test either stagnant or flowing.